竞争失效场合步进应力加速试验统计分析

竞争失效场合加速试验(AT)技术是加速试验由简单结构产品向复杂结构产品推广应用的基础.但目前的方法主要针对恒定应力加速试验.而对竞争失效场合步进应力加速试验缺乏相关研究.针对这一问题,对最一般形式(突发型失效和退化型失效并存)的竞争失效场合步进应力试验进行建模与分析.充分考虑了试验数据由于试验截尾和失效样本对应的失效模...

Analysis of Step Stress Accelerated Testing with Competing Failure Modes

The technology of accelerated testing (AT) with competing failure modes is the foundation of application extending from products with simple structures to products with complex structures. However, most of the methods proposed in relevant literature are for constant stress AT, and there is scarcely any study concerning methods for step stress AT. This article proposes a model and a method for analyzing a common type of step stress AT with competing failure modes in which both hard failures and soft failures exist. Full consideration is given to the incompleteness of testing data, which may be due to censoring as well as masking that occurs when the failure time is observed, but its corresponding failure mode is not identified. Then maximum likelihood estimation (MLE) based on expectation maximum (EM) algorithm and pseudo-lifetime MLE are proposed for analyzing respectively the hard failure modes and soft failure modes. Finally, case studies are performed to check the validity of the model and the method.